Step 1

Preheat the oven to 425°F (218°C). Grease a large baking sheet with non-stick cooking spray. You can also use a large casserole dish instead of a sheet pan.

Step 2

Add tomatoes and onions to the prepared baking sheet. Place into oven and roast for about 30-35 minutes or until tomatoes and onions are tender and soft.

Step 3

Let vegetables cool slightly then transfer to a large blender, making sure to include any juices released by the tomatoes and onions. Add pesto and chicken stock. Blend on high speed until completely smooth. Be careful as the mixture could still be hot. The soup will be quite thick. You can add more stock as needed to achieve desired consistency. (I will sometimes add about 1/2 cup or more depending on who I am serving it to).

Step 4

Transfer soup to pot and reheat over medium heat until warmed through. You can also reheat soup in individual portions in the microwave (using a microwave-safe bowl). Taste and add salt and pepper if needed.